Poster P-4 Formation of ultrafine particles in a classroom under different ventilation conditions Hak, Claudia; Vogt, Matthias; Dauge, Franck René; Fjellheim, Øystein; Holøs, Sverre Bjørn; Yang, Aileen; Mikoviny, Tomas; Wisthaler, Armin Publication details Event: EOHNANO 2019 (Loen) Date: June 3rd 2019 – June 6th 2019